Porting SII heads, carburator vs turbocharged

[The Swede]

Hi All!

I was talking with a friend that has twin turbos and a big block 3000+hp engine (www.protruck.se) about this this but he wasen't sure about it.

Is the porting work different between carburator and turbocharched?

I was just thinking about it since we have good deal on a Buch engine with full ported heads with titanium valves.

As you all know these heads where for carburator.

 

[n20junkie]

from what i know, a head ported for NA is designed to create the best port velocity and flow ratio, allowing for the ram supercharging effect for lack of a better name and the intake ports tend to be a bit smaller. but with a forced induction engine the supercharger and intake boost pressure remove the need for that port velocity, and the bigger the port the better within reason. Grant

 

[The Swede]

OK, bigger port the better?

Intake or/bouth?

What is the best flowing in these heads?

Can i ask the question again;

As we all know the Buch heads where full ported for the Buch serie, can i use these full ported heads in a 1300+ turbocharged engine without any correction in the heads?

Thanks!

/ Uffe

 

[Big Stu]

Originally posted by The Swede
OK, bigger port the better?

Intake or/bouth?

What is the best flowing in these heads?

Can i ask the question again;

As we all know the Buch heads where full ported for the Buch serie, can i use these full ported heads in a 1300+ turbocharged engine without any correction in the heads?

Thanks!

/ Uffe

Flow numbers? 340-360 intake is about what you'll get. Not many guys have heads that bad anyway. Where are you picking the busch motor up at?

 

[The Swede]

Originally posted by Big Stu
Where are you picking the busch motor up at?

Outside Karlskoga here in Sweden, approx. 1½ hours drive from me.

 

[steveX]

if you are forcing the air in, i don`t think CFM# is the main issue. but i might be worng here, you know what they say "bigger is not always better", but i this case i will stick with bigger is better (force induction). I alway shoot for maximum port volume. sometime i will go through the port walls and i will have to start over, i don`t think you can afford to do this in your application. i know of BBC N/A motor making 900hp with the best heads/porteds but when you strap a air pump (force induction) to the monster, watch the HP walk into the land of the insain....LOL.

 

[The Swede]

Looks like this is an hard question.....

steveX, thanks for your thoughts.... but, if we have a BBC N/A and then just bolt on 2 turbos, then we are on deep water....

You must rebiuld the complete engine included the camshaft that need a PC related system to calculate all in the engine...like;

The CC in the intake and exhaust channels in the heads, pistons, crank, stroke, valves and it goes on and on.....

For me it seems like no one knows this excactly, right?

OK, will talk to some guys here in Sweden, i think they know more about it.

 

[Dusty Bradford]

Maybe they don't understand what your asking. One time your talking about a complete motor, then your asking about just heads.

To me you are asking if the busch heads will work for your turbo application.

The carb heads need a smaller port for velocity and to help mix the fuel and air. A turbo fuel injected motor really doesn't care. Not unusual for a small block chevy to have really large cc runner heads on a turbo motor but you don't want to attempt that with an N/A motor. But since the Busch cars run at a constant high rpm they probably don't care about small ports.

Unless you think the head is bottle-necked somewhere, the porting will be fine. You need to make sure you have enough spring pressure and that the valve material is right for what you plan to do. I know your Titanium intakes will be fine but might want inconel on the exhaust.

 

[steveX]

cool man. let us know what you find out?